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The Honda Accord Euro
throttled by the engine management system during upshifts and downshifts, for faster, seamless shifting
and the elimination of shift shock.
Catalytic converters - one close-coupled and one underfloor - ensure emissions fall below the Euro 5
requirements.
i-VTEC
The engine uses Honda's long-established VTEC (Variable Valve Timing and Lift, Electronic Control)
system which is able to adjust the lift and opening duration of the valves. In this application it is
complemented by Variable Timing Control (VTC), creating an i-VTEC, or intelligent VTEC engine,
which takes into consideration engine load, controlling the phasing of the inlet camshaft. These systems
work in concert to produce a remarkably broad and smooth power band with exceptional torque and
horsepower.
Based on input from a position sensor located at the rear end of the inlet camshaft, together with a whole
range of other data, the engine control unit varies the inlet camshaft position relative to that of the
exhaust camshaft by means of a hydraulically driven, compact vane-type pump located on the front end of
the inlet camshaft. In this way it can advance and retard the opening of the inlet valves.
During acceleration, VTC is set at a relatively small degree of valve overlap which provides the best
output, the valve opening angle utilising the inertia of the intake air. In addition, as engine speed builds,
the VTEC mechanism switches from the low speed cam to the high speed cam (ie optimal torque to
optimal power), but with the same degree of overlap.
At high engine speeds, during motorway cruising for example, there is much greater overlap which
reduces pumping losses, maximises exhaust gas recirculation, and provides the best balance between fuel
consumption and output.
Finally, at idle and low engine speeds during light load conditions, inlet valve opening is retarded for
minimal overlap, generating strong swirl and therefore stable combustion.
Cylinder Head and Valvetrain
The Accord Euro cylinder head is constructed of pressure-cast aluminum alloy and features four valves
per cylinder actuated by dual overhead camshafts (DOHC). The cams are driven by an automatically
adjusted silent-type chain. The chain system is maintenance free and runs in an oil bath for maximum
durability. The combustion chambers have large "quench" areas to promote faster flame propagation and
more complete burning, thus helping to reduce carbon monoxide (CO) and hydrocarbon (HC) exhaust
emissions. Larger intake and exhaust valves and revised ports contribute to improved breathing. An
increase in compression ratio from 10.5 to 11.0:1 is a significant contributor to the Accord Euro's greater
power and torque output.
Crankshaft, Pistons, Engine Block and Oil Pan
Accord Euro's forged-steel crankshaft has micropolished journals to reduce friction and improve long-
term durability. The die-cast lightweight aluminum cylinder block has cast-in iron cylinder liners that are
made using a unique spin casting, centrifugal process. New-design pistons use special low-friction rings to
reduce power loss. For maximum rigidity and minimal noise and vibration, the cylinder block is a 2-piece
design that supports the five main bearings with a single cast-alloy bed-plate assembly.
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